Tuning transformer.



C. B. CAMPBELL. TUNING TRANSFORMER.

APPLICATION FI'LED FEB.16. 1917.

1 ,276, 6 l 8 I Patented 20, 1918.

3 SH SHEET 1.

15 Fla].

' 2? Hi1. 0-4 'l'O lg! Ill MI C. B CAMPBELL.

TUNING TRANSFORMER.

APPLICATION FILED FEB. is. 1911.

1,276,618. Patented Aug. 20, 1918.

3 SHEETSSHEET 2.

C. B. CAMPBELL. TUNING TRANSFORMER.

ICATI N IL 0 F 16 I APP a. .911. 1 ,27 6, 6 l 8 I Patented Aug. 20,1918..

' 3 SHIEETSSHEET-3- Hg 6 m 4 I CARLYLE B. CAMPBELL, or senior, IOWA.- 4

Tourne TRANSFORMER.

Specification of Letters Patent. Patented Aug. 20, 1918,

Application filed February 16, 1917. Serial No. 149,034.

To all whom it may concern:

Be it known that I, CARLYLE B. CAMPBELL, a citizen of the United States,residing at Sully, in the county of Jasper and State of Iowa, haveinvented certain new and useful Improvements in Tuning Transformers; andI do hereby declare the following to be a full, clear, and exactdescription of the in vention, such as will enable others skilled in theart to which it appertains to make and use the same.

This invention relates to new and useful improvements in tuningtransformers, and the principal object of the invention is to provide atransformer in which unused portions of the inductance are completelyout off from the circuit, thereby eliminating un-- desired effects onwave lengths.

Another object of the invention is to pro vide a transformer which isdivided into sec tions the .terminals of which are connected to switcheswhich connect and disconnect the windings as may be required.

A still further object of the invention is to provide adevice having inits primary circuit a-series of separate coils, the terminals of whichare connected to annular contacts and contact fingers which fingers arenormally bent to engage the contact to throw the coils in series andalso to provide a means for separating the fingers from the contact inorder to cut out certain of the coils when desired.

Still another object of the invention is to provide a'novel constructionof contact and contact 'fingers which is designed to cooperate with theswitch arm and disk carried thereby.

A still further object of the invention resides inthe provision of aplurality of separate coils the terminals of which are confingers andallow the same to move into engagement with the contact.

With these and other objects 1n view, the

invention consists in the novel combinationv and arrangement of partswhich will be fully set forth in the following specification;

Fig. 3, is an end view from the oppositev end gram of the primary of thetuning coil;

Fig. 5 is a view showing the winding dia gram of the secondary of thecoil;

' Fig. 6 is a detail plan view of the switch for controlling the primarywinding of the tuning coil;

Fig. 7 is a view similar to Fig. 6 of the switch used in connection withthe secondary winding of the device;

, Fig. 8 is an enlarged detail fragmentary sectional view of one of theswitches showing the contact and contact fingers in detail:

Fig. 9 is a fragmentary sectional view of the base showing the elevatorsecured thereto;

Fig. 10 is anenlarged fragmentary detail end view of Fig. 8; L-

Fig. 11 is a plan view of a modified form of the switch showing the samewhen the disk is eliminated;

Fig. 12 is an enlarged fragmentary detail sectional view of the basesimilar to Fig. 8,

showing the contact attached thereto and illustrating in detail themodified form of contact fingers;

Fig. 13 is an end-view of Fig. 12;

Fig. 14 is a detail edge view partly in section showing the (switchblade; and

Fig. 15 is a sectional view on line 1515 of Fig. 14 showing the'same onan enlarged scale for clearly illustrating the detailed construction.

Referring to the drawings, the numeral 1 designates the base of thedevice supporting thereon the primary designated by the numeral 2. Thisprimary consists of the usual hollow spool wound with the usual primarywindingdesignated generically by the numeral 3 which primary windingconsists of a plurality of coils of wire I) the terminals of which areindependently connected to the contact element which will be more fullyFig. 4 is a view showing the winding dia- I coil consists of a pluralityof independent coils 8 which are connected to the secondary switch whichwill be more fully hereinafter described. In the type of primary switchillustrated in Fig. 6 it will be seen that the same consists of aplurality of contacts 9 arranged in annular series and attached to astationary base 10 by means of suitable pins 11, which extend throughsaid base and are provided with nuts 12 on their inner ends. Extendingover and normally tending to engage the upper ends of the contact 9 arethe contact fingers 13 which are formed on the bight portions 14: of aplate 15 which is attached to the base by means of a bolt 16 having anut 17 threaded thereon which plate is provided with a spur 18 forengaging in the face of the plate 10 in order to hold the spring fingeragainst rotary movement on the base plate.

As previously described the finger 13 normally tends to engage thecontact 9 so as to connectthe terminal of the coil which is connected tosaid spring finger with the terminal of the next adjacent coil which isconnected to the contact.

As illustrated in Fig. 10, the side edges of each spring finger 13 areupturned as at 19 while the upper corners of the contact 9 are beveledas at 20 to allow for the entrance of the rotatahly m ounted contact armwhich will be more fully hereinafter described between the contacts andspring fingers. Secured to the base 10 centrally of the annular seriesof contacts 9 is a ivot stud 21 having rotatably mounted thereon aninsulating disk 22 which is relatively thin and provided with a radialslot 23 which forms a break in the circumferential portion of thedisk. Astop lup: 23 is formed on the disk and extends outwardly from itsperiphery adjacent one side of the slot and is adapted to engage a stoppin 24- secured to the base iln irder to limit the rotary movement ofthe c is Attached to the underside of thedisk and in electrical contactwith the stud 21 is a contact arm 25 which is adapted to engage theupper ends of the contacts 9 successively stop pin 24 and therebyprevent further movement of the disk in that direction. In

order to prevent the edge 23 of the disk 22 from separating the contactsprings 13 from the contacts 9 after the edge 23* of said disk has beenmoved so as to free said contact fingers a suitable elevator designatedby the numeral 26 is provided and consists of an 10 between the firstand last contacts 9 by means of-suitable threaded studs 28 having thenuts 29 threaded thereon.

In order to prevent the disk. from being turned in a reverse directionafter the same has reached its rearmost limit of movement the edge 23 ofthe slot 23 will engage the end edge of the plate 26 as will be clearlyseen upon reference to Figs. 6 and 9. It will be evident that when it isdesired to connect certain of the coils together and throw the same incircuit with the remaining coils, the disk 22 is rotated in a clockwisedirection thereby moving the contact arm 25 over the contacts 9 untilthe contact arm rests on the desired contact.

the top of the'spring fingers 13 lying between the contact arm 25 andthe elevator thereby allowing said fingers to engage their respectivecontacts to throw 111130 the circuit a desired number of coils. In thisway it will be seen that the effect of the loose .ends of the primarywinding on the apparatus, will be eliminated as these coils arecompletely cut out of the circuit.

In the secondary switch illustrated in Fig. 7 the contacts aredesignated by the numeral 9* while the contact spring fingers aredesignated by the numeral 13. These fingers normally tend to move intoengagement with the contacts 9 in order to cut in their respectivecoils, but owing to, the fact that the contacts are arranged only in asemicircular series it will be seen that only a semi-circular insulatingplate 30 is required.

This plate is rotatably mounted on the cen-' tral stud 31 which is inelectrical communication with the contact arm 32 secured'to theunderside of the plate adjacent one of its radial edges which contactarm engages the contacts 9". In this-construction it will be seen thatthe use of the elevator is eliminatedas the plate only makes a part of arevolution and it will be seen that as the contact arm 32 is moved in'acounter-clockwise direction from the position illustrated in Fig. 7, thecoils will gradually be cut out and will remain out of circuit owing tothe fact that the plate 30 separates the spring fingers fromthecontacts.

In the modified form of primary switch illustrated in Fig. 11, it willbe seen that the contacts are designated by the numeral 33 and arearranged in annular series as in the primary switch in Fig. 6. Thecontact arm designated by the numeral 34 is pivoted centrally of theannular series of contacts 33 and is arranged so that its ends projectover said contacts as clearly illustrated in Fig. '11. A suitableinsulating plate 35v is riveted or otherwise attached to the upper sideof said arm adjacent the end which bears on the contact 33 and both thecontact arm 34 and the insulatingplate are bevthe spring fingers 37 aredownturned as at 41 and these downturned portions are provided attheirlower corners with beveled faces 42 which cooperate with the bevelededges 43 of thecontact 33 in admitting the contact arm 34 and theinsulating plate 35.

In this construction of switch it will be seen that owing to the factthat the contact plate 35 separates the spring fingers from itsrespective contact the coils in the rear of said switch arm will be cutin while those of the forward side will be cut out of the series. Itwill be understood that the switch arm 34 is connected by a wire 44 tothe binding post 45 while the opposite binding 0st 46 is connected toone terminal of the rst section of the primary coil.- The secondary coilis connected through its switch by connecting a wire 47 to the post 31and to the binding post 48 thereby electrically connecting the switcharm 32 with the binding post. One terminal of the first coil 8* of thesecondary winding is connected to the binding post 49 while the oppositeterminal as previously described is connected to the first contact 9 ofthe secondary switch, while the first terminal of the second coil 8 ofthe secondary winding 8 is connected to the spring finger 13 whichengages the first contact 9. The opposite terminal of the second coil isthen connected to the second contact 9" as will be clearly shown in Fig.5. The same wiring system is used in the primary illustrated in Fig. 4,and it will thus be seen.

that the primary and secondary windings are separated into a pluralityof separate units having their terminals so arranged that they normallytend to contact in order to cut in the whole coil and yet capable ofbeing separated so that the units may be progressively cut in the coiland also make contact through the contact arm with the outer circuit.

In the modified form of the invention, while the unused units of thecoilare al-' lowed to be in series with each other it will be seen thatthey are separated from the portion which is being used, therelioiyavoiding any possibility of the same a ecting the .operation of theinstrument.

While in the foregoing there has been shown and described the preferredembodiment-of this invention, it is to be understood that such changesmay be made in the com-.

bination and arrangement of parts as will fall within the spirit andscope of the appended claims.

What is claimed is 1. In a transformer, a; plurality of independentcoils of wire, contacts connected to one set of terminals of the coils,contact springs connected to the opposite terminals of the coils andarranged to engage the first mentioned contacts to normally tend tocon-.

nect all of the coils in-series, a switch arm adapted to engage thecontacts and to separate the said contacts and contact springs to cutout that part of the coil ahead of the switch arm, and an insulatingplate secured to the upper side of the switcharm and 'extending betweenthe contacts of the last coil in use and the contact spring of the firstunused coil.

2. In a transformer, a plurality of independent coils of wire, contactsconnected to.

one set of terminals of the coils, contact springs connected to theopposite terminals of the coils and arranged to engage the firstmentioned contacts to normally tend to connect all of the coilsinseries, a switch armadapted to engage the contacts and to separate thesaid contacts and contact springs to cut out that part of the coil aheadof the switch arm, and an insulating plate secured to the upper side ofthe switch arm for extending between the contacts and contact springs ofthe unused portion of the coil to prevent the units from being connectedand affecting that part of the coil which is in use.

3. In a transformer, a plurality of independent coils of wire, contactsconnected to one set of terminals of the coils, contact springsconnected to the opposite terminals of the coils and arranged to engagethe first mentioned contacts to normally tend to connect all of thecoils in series, a switch arm adapted to engage the contacts and toseparate the said contacts and contact springs to out out --that part ofthe coil ahead of the from operative position with relation to theswitch arm, and an insulating plate secured contacts in the rear of theswitch arm. 10 to the upper side of the switch arm for ex- In testimonywhereof I afiix my signature tending between the contacts and contact inpresence of two witnesses.

5 springs of the unused portion of the coil to H ARLYLE B. CAMPBELL.

prevent the units from being connected and Witnesses;- aflecting thatpart of the coil which is in E. R. EVANS,

. use; and an elevator for raising the plate OLIVER Sm'rm

